1. Technical Field
The present invention relates to a printing apparatus which is able to carry out double-sided printing.
2. Related Art
In the prior art, as this type of printing apparatus, there is proposed a printing apparatus which is provided with a pair of transport rollers which are arranged at an upstream side with regard to a head, a pair of discharge rollers which are arranged at a downstream side with regard to the head, and a reversing mechanism which is provided on an upstream side of the transport rollers and which returns a sheet, which is transported from the transport rollers, to the transport rollers by reversing the front and rear of the sheet (for example, refer to Japanese Unexamined Patent Application Publication No. 2007-38562). In this apparatus, when a double-sided printing instruction is given, printing on the front surface is executed so that a sheet transport process where the sheet is transported on a platen which opposes the head is performed by forward rotating the transport rollers and the discharge rollers, and printing on the rear surface is executed so that a sheet returning process where the sheet is transported to the upstream side is performed by reverse rotating the discharge rollers such that a rear edge of the sheet is nipped by the transport rollers, the sheet is transported to the reversing mechanism by reverse rotating the transport rollers in a state where the sheet is nipped, and when the sheet is returned to the transport rollers by reversing the front and rear of the sheet using the reversing mechanism, the sheet is transported again on the platen by forward rotating the transport rollers and the discharge rollers.
In a printing apparatus which executes printing by ejecting ink from a head onto a sheet, there are cases where so-called cockling (a corrugation phenomenon) is generated where the sheet swells due to ink which is ejected from the head. Since it is difficult to transport the sheet and the possibility of a jam being generated increases when cockling is generated, it is desirable that, during the double-sided printing, transporting of the sheet be performed as fast as possible in the sheet returning process and that the sheet be nipped by the transport rollers before cockling is generated. On the other hand, in a printing apparatus which is able to carry out borderless printing where printing is performed such that a margin is not generated on the sheet, concave and convex sections are usually formed on the platen which opposes the head such that the rear surface of the sheet is not soiled by the ink even when borderless printing is executed. In a case where double-sided printing is performed by such a printing apparatus, it is easy for the sheet to be caught on the concave and convex section and there are cases where this catching may cause folding or soiling of the sheet when the rear edge of the sheet is positioned on the platen during the sheet returning process.